Abstract: 【Purpose/significance】Grave public health emergencies break out frequently, seriously threatening lives and health of 1.4 billion people. Building a scientific, unified, efficient and collaborative public health emergency command system of decision-making is an important guarantee for winning the battle against the epidemic. Therefore, it is urgent to study and reveal the collaborative rela⁃ tionship network and its evolution mechanism in emergency management of public health emergencies.【Method/process】This paper extracts node and relationship data from the multi-source text of collaborative relationship between COVID-19 decision-makers, and establishes topological graphs of collaborative relationship among decision-makers under different alert levels. Analyzes the structural characteristics of collaborative relationship network, and also reveal evolution features of the network based on complex network method.【Result/conclusion】Collaborative relationship network of decision-makers in grave public health emergencies presents the property of scale free. Its evolution mechanism is centralized and unified leadership of core decision-makers, and many decisionmakers have a collaborative relationship with other decision-makers through hub nodes. Meanwhile, network evolution has the charac⁃ teristics of core-periphery and small-world, and good collaboration efficiency and accessibility.【Innovation/limitation】Establishes a collaborative relationship network among decision-makers, and reveals its evolution mechanism and features via complex network method. Combine decision-makers with its emergency response function to explore dynamic evolution of emergency response function in the further research.